Significant efforts have been made toward enabling the utilization of smartphones as keys to access or command the operation of an equipment device, such as a door or a vehicle. Conventional systems may rely on signal strength of communications to determine relative distance and/or position between a transmitter and a receiver. For instance, many conventional systems measure signal strength with a directional antenna to determine the relative distance and/or position between a transmitter and a receiver. This conventional arrangement has several limitations, but the principal limitation is location accuracy. Several factors can affect location accuracy. Examples of such factors include physical boundaries, external objects, and moving objects, and moving aspects of the equipment device. Conventional systems may fail to achieve or maintain location accuracy in view of these or other factors.